feat(workflows): add workflow_dispatch trigger to Docker workflow

Author: StillLutto

.github/workflows/docker.yml

@@ -12,6 +12,7 @@ name: Publish Docker image
 on:
   push:
     branches: [ master ]
+  workflow_dispatch:
 
 jobs:
   push_to_registry:
@@ -53,4 +54,4 @@ jobs:
         with:
           subject-name: index.docker.io/movinglutto/undefined-docs
           subject-digest: ${{ steps.push.outputs.digest }}
-          push-to-registry: true
+          push-to-registry: true